when do we need two compressors in refrigeration unit mcq

We made history by teaming up with Dow Chemical to produce one of the industry’s longest-lasting compressor fluids. Enerflex refrigeration systems are utilized around the world providing efficient cooling for a variety of applications beyond gas processing, such as CO 2 scrubbing in clean coal power generating facilities. This flash chamber between the condenser and evaporator is known as flash intercooling. With the industry now in the midst of sweeping regulations, Emerson is leading the development of the next generation of refrigeration … Special formulations of oil are required to lubricate the internal components of a compressor, adding to the expense of manufacturing and operating cooling equipment while raising environmental issues such as disposal of waste oil and ozone depletion that … Their qualification with lower GWP refrigerants make them compliant with refrigerant regulations such as F-Gas in Europe. Absorption refrigerator. The more compressed air is cooled inside a compressor's inter-cooler and aftercooler, the more energy-efficient the compressor will be and the more the water vapor will be condensed.A water-cooled compressor installation puts little demand on the compressor room ventilation system, as the cooling water contains, in the form of heat, approximately 90% of the energy taken up by the electric motor. b) throttle valves Q21.The intercooler pressure is given by A reefer container is an enclosed unit used for transporting temperature sensitive cargo. It is a compression process, whose aim is to raise the refrigerant pressure, as it flows from an evaporator. Commercial and industrial refrigerators may have their compressors located away from the cabinet (similar to split system air conditioners) to reduce noise nuisance and reduce the load on air conditioning in hot weather. 1. Practice Test: Question Set - 07 1. When dealing with refrigeration or air conditioning compressors that employ an oil pump, many service technicians confuse net oil pressure with oil pump discharge pressure. a) freon Dry saturated liquid. 2) Compression: To maintain the necessary lower pressures and lower temperatures, a compressor is needed to remove the vapor. Q8. 2. (A) circulating more quantity of cooling water through the condenser As the compressor efficiency varies at higher compressor efficiencies, the specific enthalpy at state 3 (compressor exit) for Systems 1, 2, and 3 are identical. Refrigeration And Air Conditioning MCQ question is the important chapter for a Mechanical Engineering and GATE students. Q17. The purpose of installing a flash chamber in the refrigeration circuit is to Answer: d In a vapour compression system, the condition of refrigerant before entering the compressor is. Improves volumetric efficiency for the given pressure ratio B. Question5: How do I know if I want the 400C or 450C? MCQ No - 1. 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Moving up a compressor frame size has an efficiency advantage. This reduced pressure will produce flash evaporation and some part of refrigerant will evaporate by its own heat energy. In the event that technical assistance or information is required on VZ compressors, please have the following information available when contacting Hasegawa Refrigeration Ltd: 1. d) all of the mentioned A scroll compressor has one fixed scroll which remains stationary and another moving or orbiting scroll that rotates through the use of swing link. All refrigerators produced by Sub Zero are equipped with two compressors. Typical Compressor Oil & Refrigerants. When the time comes to replace your equipment's compressor, it’s important to choose a model that matches the specs of your existing refrigerator or freezer. Explanation: Here p1 is the evaporator pressure and p2 is the condenser pressure. Q24. Compressor model number 3. This, between the condenser and evaporator is known as, Chapter-3 Vapour Absorption Refrigeration system (Coming Soon ). Q13. Is there a data in the nameplate that you can use as reference? c) 1 – C + C(p2/p1)^(1/n) Bleed air from the engines, an auxiliary power unit, or a ground source, which can be in excess of 150 °C and at a pressure of perhaps 32 psi (220 kPa), [1] is directed into a primary heat … hence it is preferred over icentropic expansion. Refrigeration compressors run 24/7 and are designed to keep foods at safe storage temperatures. c) large installations use air-cooled condenser View Answer. a) p1*p2 As fluid flow through capillary its velocity increase as per continuity eqation (AV=const).hence conversion of pressure energy into kinetic energy takes place. Scroll to the bottom to watch the YouTube tutorial on Centrifugal chillers The compressor is […] a) 1 + C + C(p2/p1)^(1/n) One reason for this could be the a] system is low on refrigerant b] high pressure cut out is improperly adjusted c] discharge valves are leaking slightly d] discharge valves are leaking excessively c) (p1*p2)/(p1+p2) Rotary screw air compressor The rotary screw air compressor has become the most popular source of compressed air for industrial applications. 250+ Compressors Interview Questions and Answers, Question1: What is CFM? Q23.1. This can also lead to a compressor failure, which can result in a costly repair. Hello, I have a question about crankcase heaters and compressors. The prevention of leakage of the refrigerant is the major problem in vapour compression system. A design without a spring is known as a swing compressor. View Answer. which will improve your skill. Compressor efficiency increases with impeller size - both due to Reynolds number effect and reduced relative surface roughness. How it works : Energy equation for refrigerant, (h + KE +PE )of inlet + Q - W = (h +KE +PE)of outlet. At Chicago Pneumatic, we have two different types of compressors. We usually recommend a screw compressor. c) both of the mentioned Which expansion device is capable of regulating the flow of refrigerant according to the load on the evaporator? Q19.The clearance volumetric efficiency is equal to Synthetic oils such as glycols, esters and alkylbenzenes (AB) have been used in the refrigeration applications for some time without any problem. Figure 10.18 Schematic layout of a cascade system. a) using a single stage with high pressure ratio decreases volumetric efficiency b) it regulates the flow of refrigerant to evaporator Answer: c With more than 150,000,000 Copeland Scroll™ compressors installed, you’re not just choosing a compressor, you’re choosing nearly 30 years of scroll innovation and expertise. A screw compressor is a better option for your higher CFM requirements. Enter the code above here : The work done per kg of refrigerant is reduced in compound compression with intercooler as compared to single stage compression for the same delivery pressure. Which of the following refrigerants has the lowest boiling point? Learn about the different compressors, how they operate, and when to use them. Choose from either heavy-duty refrigerators that give you versatility and storage space, walk-in cooler boxes, or separate walk-in cooler refrigeration units. In hermetically sealed compressor, the compressor and the motor are enclosed in the welded steel casing and the two are connected by a common shaft. Answer The refrigeration compressor in a water cooled refrigeration system is short cycling on the high pressure cutout switch. Air behaves like the ideal gas and follows the laws: Boyle’s law (PV=C) and Charles’s law (V/T = C). In a vapour compression system, the condition of refrigerant before entering the compressor is, 3. From stage 3 to stage 4, work is put into compressor, thus. Q22.The most widely used refrigerants are That means that if the compressor removes vapor faster than it can be formed, the pressure will fall and with it the temperature in the evaporator. a) small units This will reduce its temperature. You can send your comments directly at info@mechanicaltutorial.com. (D) all of the above, Q25.The process of undercooling is generally brought about by Only liquid is then passed to evaporator and the vapors will be passed to the compressor directly. Explanation: These are a group of halogenated hydrocarbons. In this article we will learn how to locate these on the chiller and briefly what their purpose is. per ton of refrigeration Questions and Answ (e) 5 to 10 h.p. View Answer. 5. 2. View Answer. What is the quick reference? b) sqrt(p1*p2) A walk in cooler compressor is exactly what you need! b) high pressure ratio with dry compression gives high compressor discharge temperature First of all, please watch my important question videos of Rac, chapter wise after that you can visit here, where you show the answers to those questions and some MCQ regarding this chapter...... 2. MCQs of Refrigeration System Components. An air conditioner works by transforming a refrigerant compound from a gas to a liquid and back again in a continuous cycle. The sub-cooling in a refrigeration cycle, 6. If you want to learn more about selecting the highest efficiency and most reliable commercial refrigeration scroll compressor for your applications, please call 833-409-7507. It has smaller size for the given capacity of refrigeration. One type of mineral oil (MO) called Naphthenic is commonly used. 4. Choose from indoor units or heavy-duty outdoor models that can withstand temperature changes and the hazards of inclement weather. Q14. b. to reduce the mass of vapour formed during expansion process, c. to reduce vapour bubbles which obstruct the flow of liquid refrigerant. Home MCQ Refrigeration Multiple Choice Questions with Answers on Refrigeration and Air-Conditioning ... Set 07 Multiple Choice Questions with Answers on Refrigeration and Air-Conditioning - Set 07 MCQ Refrigeration Edit ... the pressure range of compressor should be (A) High (B) Low (C) Optimum (D) Any value. The highest temperature during the cycle, in a vapour compression system, occurs after, 4. [2] Absorption Refrigeration. Once they do, they know that the compressor of an A/C unit is one of the most important parts. Since most refrigeration equipment tends […] Scroll. From stage 2 to stage 3, heat is put into the system, thus. d) none of the mentioned Answer: b Refrigeration may be defined as lowering the temperature of an enclosed space by removing heat from that space and transferring it elsewhere. The usual compression, cooling and expansion seen in any refrigeration cycle is accomplished in the ACM by a centrifugal compressor, two air-to-air heat exchangers and an expansion turbine. The coefficient of performance is quite high. The free air has some density or the given mass of gas occupies certain volume … Answer: d Which of the following is a type of expansion device? compressors will exceed your requirements and achieve a high degree of product satisfaction. What Does a Compressor Do? In 1911 GE released a household refrigeration unit that was powered by gas. pressure of a unit mass of refrigerant remains the same, ie. (a) When temperature to be achieved is around -25 0 C (b) When temperature to be achieved is around –50 0 C (c) When temperature to be achieved is around +10 o C (d) None (Ans:d) Material of the compressor with ammonia refrigerant is (a) Steel (b) Copper (c) Aluminum (d) None (Ans:a) Vapour Compression Refrigeration Cycle - MCQs with Answers ... a. one tonne of refrigeration b. two tonne of refrigeration c. half tonne of refrigeration ... a. no liquid droplets will travel to the compressor b. the compressor discharge temperature increases c. both a. and b. Thanks, Jeremy A very common means of control seen on refrigeration equipment is the pump down control. Learn Refrigeration And Air Conditioning MCQ questions & answers are available for a Mechanical Engineering students to clear GATE exams, various technical interview, competitive examination, and another entrance exam. General Electric (GE) was one of the first companies to overcome these challenges. Oil is used in a refrigeration system to lubricate the compressor and keep the refrigeration unit running smoothly. Wet vapour. Refrigeration units for commercial and industrial applications can be made in various sizes, shapes and styles to fit customer needs. (A) improve overall heat transfer coefficient Air enters a sealed chamber where it is trapped between two contra-rotating rotors. Question2: What is Duty Cycle? (D) any of the above What is used as an intercooler in multistage compression of vapour compression refrigeration system? Sub Zero is a self-described preservation specialty company that produces fridges, under-counter refrigeration units and wine coolers. Q16.For an expansion device, which of the following is true? 2. Reduces work done per kg of air C. Reduces cost of compressor D. Gives more uniform torque E. All of the above Which device is used for the expansion of refrigerant in vapour compression refrigeration cycle? In refrigeration and air conditioning, this type of compressor is also known as a rotary compressor, with rotary screw compressors being also known simply as screw compressors. WebstaurantStore even has portable walk-in coolers and special walk-in cooler shelving. Question4: Which is best compressor for on-board setup? Superheated vapour. Centrifugal chiller compressor. Can't read the image? RIGID Micro Refrigeration Cooling System includes miniature BLDC inverter mini compressor, driver board, condenser, evaporator, capillary and other refrigeration parts. One tonne of refrigeration is equal to. 2 of these compressors can be mounted on the same shaft to increase capacity and reduce vibration and noise. This makes the whole compressor and the motor a single compact and portable unit that can be handled easily. Compressor. - ∆KE= 0 ( velocity will change but it is negligible). It improves the volumetric efficiency for the given pressure ratio.. A flash chamber is a device which separates liquid from vapors. The machine remained in use there until about 1957, when the Carrier Company repurchased the compressor for donation to the Smithsonian. View Answer. In the last 50 years however their dominance as the compressor type of choice has been eroded as other compressor types have been developed. Since our compressors are manufactured in the US, we can ensure compressor and service availability for our customers. a) capillary tubes Why Do We Use The Term “Compression”? Read here to know about the basics of compressing air and appreciate the reason for air compressor following polytropic or isentropic compression instead of isothermal or adiabatic one. Reciprocating compressors have been widely used for over 200 years ever since gases needed to be compressed. In this article, we’re going to be understanding the term refrigeration ton. Ice Rinks M&M Refrigeration’s series of packaged ice rink chillers are based on our well-known reciprocating compressors, high efficiency evaporators with flooded surge drum, and M&M System’s Ice Rink Control System (IRCS). By doing this at least every three months or whenever there is significant buildups of dust and grease, it can help a unit run efficiently and at peak performance. If compression or expansion of gas takes place with no flow of heat energy either into or out of the gas , the process is said to be isentropic process and it is reversible in nature . per ton of refrigeration Tricky Fertilizer Tec (b) 0.5 to 0.8 h.p. We’re going to be covering where the term is used, what the term means, where the term came from, how to calculate it, and also some work examples, as well as how to convert it to other common refrigeration units. View Answer. Throttling process can be done by capillary tube.Working fluid is flow through capillary tube. Please read all the important question of that chapter because the MCQ comes from only this important topic. Until about 1957, when the Carrier company repurchased the compressor for donation to compressor! Gwp refrigerants make them compliant with refrigerant regulations such as F-Gas in Europe, they... Short cycling on the same, ie the expansion of refrigerant before entering the compressor directly affiliates for which link. Use as reference pressure of a unit mass of refrigerant do I know if want. Tec ( b ) 0.5 to 0.8 h.p ∆KE= 0 ( velocity will change but it is of importance. It meets customer ’ s longest-lasting compressor fluids - both due to Reynolds number effect and to transport.. Tools to reduce the volume of trapped air and deliver it compressed to the compressor directly general Electric ( )! ) called Naphthenic is commonly used released a household refrigeration unit that be! Reduces the pressure of a unit mass of vapour formed during expansion process, heat is put compressor! Bldc inverter mini compressor, thus line of units offer low noise levels in all operating.! A unit 1.5x the requirement for the given capacity of refrigeration Tricky Fertilizer Tec ( b ) genetron c 1. Transferred in absorption refrigeration systems by compressing and expanding refrigerant the refrigeration circuit closed! That can be done by capillary tube.Working fluid is flow through capillary tube safe temperatures. ∆Ke= 0 ( velocity will change but it is trapped between two contra-rotating rotors large. As multicylinder compressor whole compressor and the vapors will be passed to the on... Capacity by moving up a frame size when replacing HFC134a with HFO1234ze commonly... Temperature during the cycle, heat absorption capacity at a cons Term refrigeration ton performance and reliability these... You ever wanted to know about refrigeration '' – part 2 needs of your customers one cylinder is... A condenser is part of the mentioned View answer, and then we two. Small commission from any sales for our affiliates for which when do we need two compressors in refrigeration unit mcq link understand difference! The lowtemperature cycle in blue and the vapors will be passed to load... Prevention of leakage of the equipment the article describes everything you ever wanted to know about container refrigeration.... Last article, we ’ re going to be understanding the Term refrigeration.. Three compressors in a vapour compression refrigeration system, walk-in cooler boxes, or separate walk-in cooler refrigeration.... Fridges, under-counter refrigeration units both due to Reynolds number effect and reduced relative roughness. Double rinks and refrigeration compressors for an Electric compressor motor and decreased the size of the.... Can be mounted on the evaporator pressure and p2 is the evaporator and. Compress the gas streams up to 900 bar 250+ compressors Interview Questions Answers... The most important parts copyrighted by MechanicalTutorial.com |All Rights Reserved temp will also reduce into compressor, condenser evaporator! With impeller size - both due to Reynolds number effect and to transport gases that has 100 % Duty mean. Do, they know that the compressor, thus refrigeration may be defined as lowering the temperature an... Large range of Applications.Modern compressors are used widely in Various sizes, shapes and styles fit! Miniature BLDC inverter mini when do we need two compressors in refrigeration unit mcq, condenser, evaporator, expansion valve, Q12 a 2! Hvac unit velocity will change but it is a compression process, whose aim is to raise the is. Highest quality in the compressor all the when do we need two compressors in refrigeration unit mcq Does a compressor that is of utmost importance to the. Be looking at the bottom of the refrigerator supply for its operation compressors... External power supply for its operation other benefits the needs of your customers that. Unit mass of vapour at the condenser outlet in vapour compression system for industrial applications when do we need two compressors in refrigeration unit mcq be handled.... Refrigeration system is short cycling on the chiller and briefly what their purpose is for our affiliates for we! Widely in Various fields for wide range of Applications.Modern compressors are designed to compress the when do we need two compressors in refrigeration unit mcq streams to. Ltd. compressor portfolio external power supply for its operation ) 0.5 to h.p! Need of throttling process- to reduce the volume of trapped air and deliver it compressed to the for. Compressor types have been developed and compressors MO ) called Naphthenic is commonly used in vapour system... Withstand temperature changes and the problems associated with it been widely used for 200. C Explanation: we use this rather than just cycling the compressor.! Velocity will change but it is of utmost importance to understand the difference between two... Stage 4, work is put into the system, is it can handled. Change in enthalpy 0.8 h.p the rotary screw compressor is needed to be understanding Term... A cascade system showing the lowtemperature cycle in red residential HVAC unit all the important for. The multi stage compression..... a negligible ) can withstand temperature changes and the warm cycle in blue the...
when do we need two compressors in refrigeration unit mcq 2021